Effects of titanium‐coated micromachined grooved substrata on orienting layers of osteoblast‐like cells and collagen fibers in culture

Abstract

Osteogenic cells from newborn rat calvariae were cultured on titanium surfaces on which cell orientation could be manipulated. Substrata included smooth surfaces and substrata with smooth regions (gaps) flanked by grooves of 47-μm pitch and 3-, 10-, or 30-μm depth. Orientation angles of the cells were measured over time using propidium-iodide staining and confocal laser scanning microscopy. In addition, collagen fibers were identified using picro-sirius staining and reflected light polarization microscopy. Grooves proved effective in orienting cells, but their orienting ability decreased above the ridge level. Cells on the smooth surface showed no preferred orientation. Cells in the gaps became oriented as a result of cell–cell interactions with the cells on the flanking grooves. Cells in grooves produced oriented collagen fibers, but in the gaps, fibers could be parallel, perpendicular, or diagonal to the grooves. Collagen fibers on the smooth surfaces formed arrays of parallel fibers in a crisscross pattern. In long-term cultures, bone-like nodules were formed, but mostly above the ridge level. These data demonstrate that grooved surfaces can influence cell orientation both in cell populations above the cells in contact with the grooves and in cell populations adjacent to the grooves. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 70A: 206–218, 2004